Cross-national study of diagnosis of the mental disorders: a comparative psychometric assessment of elderly patients admitted to mental hospitals serving Queens County, New York, and the former borough of Camberwell, London.

In a cross-national comparison of the frequency of occurrence of various diagnoses among elderly psychiatric patients admitted to public mental hospitals in London and New York, a short battery of psychological tests was administered to all patients independently of psychiatric examination. The psychological assessment was focused on the differentiation between dementing and affective disorders. The test performance showed a highly significant difference between the two groups as diagnosed, and when patients were allocated to groups on the basis of tests alone these allocations showed a high rate of agreement with initial psychiatric diagnosis. There was a similar high rate of agreement between test allocation and hospital diagnosis in the U.K., but this was not so in the U.S. No significant differences were found between the test performance of U.K. and U.S. patients, except on the WAIS Vocabulary and the Angles Error measurement of the Bender-Gestalt test. When the effects of age and Vocabulary score were eliminated these differences disappeared. The hypothesis that the diagnosis of affective disorder would be confirmed by a relatively greater improvement in test performance over time in this group of patients was not upheld by the non-parametric analysis of change scores. However, an analysis of covariance utilizing age and initial score did indicate the expected differential improvement.